Sheet-transporting assembly

ABSTRACT

A sheet-transporting assembly including a continuous suction conveyor which operates continuously to carry previously die-cut and stripped cardboard blanks to a predetermined location whereat a vertically reciprocal grid system activated by an automatic signal operates to separate the said blanks from the conveyor and deposits the blanks upon a descending pallet elevator system.

United States Patent Joseph E. Foster, Jr.

723 Lincoln Hwy., Exton, Pa. 19341 Jan. 7, 1970 Jan. 1 l, 1972Continuation of application Ser. No. 730,073, May 17, 1968. Thisapplication Jan. 7, 1970, Ser. No. 1,119

inventor Appl. No. Filed Patented SHEET-TRANSPORTING ASSEMBLY 3 Claims,10 Drawing Figs.

U.S. Cl 271/74, 271/88 Int. Cl B65h 29/32 Field of Search 271/74, 68,

References Cited UNITED STATES PATENTS 2,969,869 l/196l Klinger 271/74 X3,205,999 9/1965 Thomas... 271/74 X 3,305,233 2/1967 Cody 271/743,477,558 11/1969 Fleischauer 271/74 X 3,490,764 1/1970 Muller et a1.27/74 Primary Examiner-Joseph Wegbreit Altorney- Karl L. SpivakPATENTEUwmm 3.333303 SHEET 2 UF 6 JOSEPH E. FOSTER, JR.

KM/ W PATENTED m1 1 m2 3533903 SHEET 3-0F 6 INVENTOR= JOSEPH E.FOSTER,JR

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PATENTEDJAN: 1 1912 31533903 sHmuuFe FIG. 30 98 hlln mh INVENTOR= c I BYJOSEPH E.FOSTER,JR.

PMENIEU ma 1 m SHEET 6 BF 6 |NVENTOR= JOSEPH E. FOSTER,JR.

SHEET-TRANSPORTING ASSEMBLY BACKGROUND OF THE INVENTION This inventionis a continuation of my copending application Ser. No. 730,073 filed May17. 1968, and entitled Continuous Suction Conveyor Stacker."

This invention relates in general to the paper-converting industry andmore particularly is directed to a sheet-transporting assembly findingutility in stacking previously die-cut and stripped cardboard stock.

The present invention is designed for use in the paper-convertingindustry in the cutting and creasing operations. It is present practiceto employ automatic cutting and creasing machines to cut and creasepaper stock from one tenthousandth to one hundred-thousandth of an inchin thickness. These machines deliver the paper stock automatically inskid loads approximately 4 to 5 feet in'height with the die-cut wasteportions still attached.

There is also automatic equipment in use for stripping previouslydie-cut and creased cardboard blanks, but such equipment must be set upand timed to match each particular product that is fed from thediecutting machine. The instant machine improves over the prior art inthat it is the only machine available that will strip all internal andexternal waste from die-cut blanks without setup, that can carry thefinished product uniformly after it is free of waste and then stack thesaid blanks onto pallets continuously to obtain piles of anypredetermined, desired height.

The machine is capable of handling 4,000 previously die-cut and strippedsheets per hour without requiring setup. The machine is unique in thatit is not necessary to orient or time the die-cut sheets to the machinein order to remove the waste portions of the sheet and to stack them ona skid in an even pile in the order in which they were cut. Applicant isaware of no other prior art devices designed for and capable ofautomatically and continuously stripping the waste from die-cutcardboard stock and transporting the stripped sheets for stacking uponpallets.

Prior art cardboard stock handling machines have utilized suctionconveyors to transport the sheets from one location to another. Suchdevices generally function as designed and are suitable for the useintended. However, in order to separate the sheet being transported fromthe suction conveyor, prior art machines have incorporated mechanismseither to intermittently stop the conveyor or the suction fans in orderto deposit the transported sheets at the desired terminal location. Theintermittent starting and stopping of the equipment necessarily limitsthe speed of the operation and in addition, causes increased maintenanceexpenditures due to mechanical wear of the moving parts. Additionally,prior art cardboard stock handling machinery required normal adjustmentand considerable setup time to compensate for cardboard stock ofdifferent sizes. The additional setup time and workers time required inorder to accommodate sheets of different sizes has resulted in greatlyincreased handling costs during normal operating periods.

SUMMARY OF THE INVENTION The instant device seeks to overcome theshortcomings of prior art machines by providing a means and method oftransporting paper stock from one location to another across the machinein a continuous manner without interruption or stoppage of the operatingcycle. In addition, means have been provided to automatically separatethe cardboard stock from the suction conveyor while the conveyorcontinuously moves and to deposit the die-cut and stripped sheets uponan elevating pallet capable of continuously descending in response toautomatic signals monitoring the height of the pile of blanks depositedthereon.

A unique cardboard blank separating grid system compris ing a pluralityof wires passing through the suction conveyor and capable of reciprocalmotion therethrough at right angles to the plane of operation of theconveyor functions to disassociate the cardboard blanks from theconveyor at a predetermined location without interruption to orinterference with the continuous operation of the suction conveyor.

It is therefore an object of the instant invention to provide animproved, sheet-transporting assembly of the type set forth.

It is another object of the instant invention to provide asheet-transporting assembly capable of stripping, transporting andstacking 4,000 previously die-cut cardboard blanks per hour.

It is another object of the invention to provide a novelsheettransporting assembly capable of transporting and stackingpreviously die-cut cardboard blanks in a continuous manner withoutintermittently stopping the suction conveyor.

It is another object of the instant invention to provide asheet-transporting assembly incorporating grid system functioning atright angles to the direction of travel of the conveyor.

It is another object of the instant invention to provide a novel,sheet-transporting assembly incorporating a grid system comprising aseries of wires passing through portions of the suction conveyor andhaving reciprocating motion with respect thereto.

It is another object of the instant invention to provide a novel,sheet-transporting assembly including a pallet elevator system toreceive the previously die-cut and stripped cardboard blanks.

It is another object of the instant invention to provide a novel,sheet-transporting assembly including a pallet elevator systemresponsive to signals to automatically lower the pile so that succeedingsheets of cardboard stock can continuously be placed on top to form apile of predetermined height for easy handling.

It is another object of the instant invention to provide a novel,sheet-transporting assembly including in one machine the operations ofvibrating cardboard blanks, removing waste portions from previousdie-cut operations, transporting the said die-cut and stripped sheetsupon a continuous suction conveyor and depositing said sheets upon adescending pallet elevator system.

It is another object of the instant invention to provide a novelstripping and stacking machine capable of handling finished productsuniformly without nicking them together.

It is another object of the instant invention to provide a novel,sheet-handling assembly that is rugged in construction, simple in designand trouble-free when in operation.

Other objects and a fuller understanding of the invention will be had byreferring to the following description and claims of a preferredembodiment thereof, taken in conjunction with the accompanying drawingswherein like references characters refer to similar parts throughout theseveral views and in which:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a right front perspectiveview of the device showing the stripping mechanism and suction andpressure chambers.

FIG. 2 is a rear perspective view of the assembly showing the descendingpallet elevator system.

FIG. 3 is a partial cross-sectional view taken along line 33 of FIG. Ilooking in the direction of the arrows and showing generally the fronthalf of the machine.

FIG. 3a is a partial cross-sectional view taken along line 3- 3 of FIG.1, showing generally the rear half of the machine and continuing theview of FIG. 3.

FIG. 4 is a partial, cross-sectional view similar to FIG. 3a showing thegrid system in lower position.

FIG. 5 is a top plan view of a perforated suction box.

FIG. 6 is a cross-sectional view taken along line 66 of FIG. 4, lookingin the direction of the arrows.

FIG. 7 is a cross-sectional view taken along line 7-7 of FIG. 5, lookingin the direction of the arrows.

FIG. 8 is a left front perspective view of the device.

FIG. 9 is a detail view of the perforated suction box.

DESCRIPTION OF THE PREFERRED EMBODIMENT Although specific terms are usedin the following description for the sake of clarity, these terms areintended to refer only to the particular structure of my inventionselected for illustration in the drawings and are not intended to defineor limit the scope of the invention.

Referring now to the drawing, it will be seen that the device consistsgenerally of a vibrating and stripping section generally designated Awherein previously die-cut cardboard blanks 14 are fed by the cutter andcreaser (not shown) toward the impactor 12 for vibrating the wasteportions free from the blank as will hereinafter be more fully setforth. The stripped blank 14 then travels across the machine upon theunderside of the suction conveyor system generally designated B. Thesuction conveyor system B integrally incorporates the verticallyreciprocating grid system C which functions to precisely separate thepreviously stripped blanks from the suction conveyor system B and todeposit the blanks upon a pallet carried by a descending pallet elevatorsystem herein generally designated D.

A pair of cooperating upper and lower feed rollers l6, l8, feedindividual cardboard blanks 14 over the finger section 22, to receivemultiple impacts imposed by the rotation of the impactor 12. The cornersof the rectangular impactor l2 protrude through the finger section 22and impart multiple impacts upon the underside of the cardboard blanks14 in the manner previously fully illustrated and disclosed in UnitedStates Pat. No. 3,270,929. Preferably, the impactor 12 rotates at 3000r.p.m. for optimum results. As illustrated, the impactor is constructedof square cross-sectional configuration and thereby provides fourstriking surfaces each revolution. It is therefore seen that theimpactor is capable of striking the cardboard blanks 14 at a rate of12,000 times per minute when rotating at optimum speed. In accordancewith the teachings of US. Pat. No. 3,270,929, it can be appreciated thatthe forward edge of the blank 14 vibrates freely upon contact with theimpactor 12 after it feeds through the intake rollers 16, 18.

Similarly, the trailing edge of the blank 14 vibrates freely due to thecontacts of the impactor 12 when the forward edge of the blank 14 feedsinto the nip of the upper and lower discharge rollers 24, 26. Thecombination of the vibrating action of the sheet itself and the force ofthe multiple rotary blows of the impactor cooperate to shake the die-cutscrap sections 36 free from the usable portions of the blank sheet 14.

An upper blower 28 powered by an electrical motor 30 pressurizes thechamber 32 which is sized to substantially over-lie the area defined bythe intake rollers 16, 18 and the discharge rollers 24, 26. In thismanner, air from the blower 28 impinges upon the upper surface of theblank 14 to force the lower surface of the blank 14 into positionagainst the finger section 22 to continuously receive impacts from therotary impactor 12. The pressure of the air from the blower 28 furtherserves to assure maximum contact between the impactor and the blank 14as the blank 14 feeds through the vibrating and stripping section A. Thelower blower 34 receives its suction through the waste removal chamber38 and serves as a vacuum-cleaning operation in cooperation with theimpactor 12. The waste particles 36, which are vibrated free by theoperation of the impactor l2 and the vibrating action of the leading andtrailing edges of the blanks 14 as they pass respectively between therollers l6, 18, 24, 26 are pulled by the vacuum of the lower blower 34through the waste removal chamber 38 for ultimate disposal at the fandischarge 40. A motor 42 powers the lower blower 34 through aconventional drive 44 in a well-known manner.

Following removal of the waste particles 36, the blank 14 travelsrearwardly out of the vibrating and stripping section Av under impetusof the upper and lower discharge rollers 24, 26 through the lower roller46 and upper segmented skate roller 48 which cooperate to drive thestripped blanks onto the suction conveyor system B.

The suction conveyor rolls 52, 54 are rotatively carried respectively onthe shafts 56, 58 which are journaled through the right and left machinesupports 64, 66 and rotate affixed sprockets for chain drive purposes.The driving motor 60 functions to rotate the suction conveyor 50 whichis trained about the roll-affixed sprockets through a chain drive 70.The chain drive 70 operatively connects to a direct-connected drivinggear 62 and to a driven gear 68 which may be pinned or otherwise affixedto the end of the leading suction roll shaft 56 in the usual manner.

Referring now to FIGS. 5, 6 and 7, the suction conveyor 50 comprises anendless chain rotating about the leading and trailing suction rolls 52.54 and includes a plurality of horizontally juxtaposed, elongated,perforated, transverse, suction boxes 72 which are operatively affixedto the supporting conveyor links 74 as required for longitudinal androtative motion with respect to the stripping machine 10. Each suctionbox 72 comprises a plurality of transverse segments 76 joined togetherthrough the longitudinal, arched junctions 78 which rise above the floorof each segment to provide a plurality of spaced, longitudinal,grid-receiving slots 80. The floor 82 of each segment 76 is drilled orotherwise provided with a plurality of openings 84 as hereinafter willbe more fully set forth. Each suction box 72 is substantiallychannel-shaped in cross section having the openings 84 drilled throughthe web section between the right and left flanges 86, 88. Each segment76 is preferably provided with five suction openings 84 ofelevensixteenths inch diameter each and arranged in a cross pattern foroptimum operating efficiency.

Fans 96 overly the medial portion of the suction conveyor 50 and arepowered through a belt drive 92 by the electrical motor 30 in well-knownmanner. The fans 96 draw their suction directly through the multipleopenings 84 provided in the suction boxes 72 and thus create sufficientsuction pressure to attract and carry the cardboard blanks 14. The fansdischarge directly upwardly through a discharge plenum 98 throughoperatively affixed suction control louvers 100. The louvers 100 may bemanually operated as a conventional volume damper in the usual manner toprecisely control the air volume and thus the suction pressure imposedat the suction openings 84. In this manner, the suction pressureavailable at the conveyor 50 may be readily adjusted as required to pickup and carry previously die-cut and stripped cardboard blanks 14 acrossthe conveyor for deposit upon the deelevating pallet system D" ashereinafter more fully discussed.

Referring now to FIG. 3a a reciprocating grid system C" comprising aplurality of spaced, horizontally disposed, longitudinal, separatingwires 104 may be observed. Each wire 104 longitudinally stretchesbetween the front and rear grid bars 106, 108, which are reciprocalbetween an upper position and a lower position 112 (FIG. 4) in responseto automatic sensing devices as will hereinafter be more fullyexplained. Each grid wire 104 respectively lies within the alignedsuction box slots 80 and permits longitudinal motion of the suctionboxes with respect therewith as the conveyor 50 rotates about the rollsS2, 54. Individual tumbuckles 114 function to permit individual tensionadjustment of the respective grid wires 104.

The front and rear grid bars 106, 108, vertically reciprocate a distanceof approximately 2 inches in response to operation of the air cylinder120. The vertical reciprocal distance must be sufficient to positivelyseparate the cardboard blanks 14 from the suction attraction of theblowers 96. A sensing device 122, which may be an electric eye, amicrolimit or suitable combination of the two, precisely senses theleading edge of the blank 14 when the blank is transported to a positionover the deelevating pallet system to activate the air cylinder 120. Theair cylinder functions through the crosshead 124 and quickly lowers theentire grid system and the affixed front and rear grill bars 106, 108approximately 2 inches, thereby forcing the blank 14 downwardly awayfrom the bottom of the suction boxes 72 to release the blanks from theattraction of the suction forces impressed at the openings 84 by theblowers 96.

The right and left sleeve bearings 126. 128, 130, 132 journal thevertical grid shafts 134, 136 and facilitate rapid, aligned, reciprocalmovement of the grid system C.

The deelevating pallet system D receives the cardboard blanks 14 whichare transported by the conveyor system B and released therefrom by theseparating action of the grid system C. A horizontal platform 138provides the base of the deelevating pallet system D" and functions toremovably receive pallets (not shown) in well-known manner upon whichthe previously die-cut, stripped and transported cardboard blanks 14 areautomatically piled as herein set forth. The individual pallets may beremoved from the platform 138 after being loaded by using conventionalforklift trucks in the usual manner. The platform 138 securely restsupon the transverse supports, 140, 142 which in turn are end carried bythe elevating chains 144, 146, 148, 150. Right and left clutch brakes152, 154 turn the respective elevating shafts 156, 158 through geardrives 160, 162 in the usual manner to rotate the respective chain gears164, 166, 168, 170, which are affixed respectively upon the shafts 156,158.

The chains 144, 146, 148, 150 rotatively engage the teeth of the gears164, 166, 168, 170 to thus raise or lower the platform 138 in responseto the operation of the clutch brakes 152, 154. The counterweights 172,174, 176, 178 respectively end connect to the chains 144, 146, 148, 150and serve to equalize the weight of chains about the gears 164, 166,168, 170 in the usual manner to compensate for movement of the chains.

A second sensing device 180, which may be an electric eye circuit,determines the height of the pile 182 of cardboard blanks 14 depositedupon the platform 138 and functions to lower the platform 138 byactivating the clutch brakes 152, 154 in response to the buildup of thepile 182 by successive deposits of transported blanks. In this manner,the tope 184 of the pile may be maintained at a constant verticaldistance from the bottom of the suction conveyor 50 at all times inresponse to the operation of the sensing device 180. When the pilebecomes 4 or 5 feet in height as predetermined by the operator, theentire pallet (not shown) with the pile 184 of stripped cardboard blanks14 may be removed from the platform 138 by utilizing the usual forklifttype of equipment and a new pallet can then be inserted in lieu thereofto receive further deposits of stripped and transported blanks.

lclaim:

1. In a sheet-transporting assembly for individually carrying sheets ofmaterial, the combination of A. a continuous suction conveyor carryingthe said sheets by fan suction forces,

1. said suction conveyor including a plurality of parallel, transversesuction boxes arranged in an endless loop, each said suction box beingprovided with a plurality of suction openings,

2. each suction box being provided at the bottom thereof with aplurality of spaced, grid wire receiving slots,

a. said slots extending in the direction of sheet travel and beinglongitudinally aligned to define continuous grid wire receiving areas;

B. sensing means detecting the leading edge of each sheet at a preciselocation along the suction conveyor to activate the grid means toseparate the sheet from the suction conveyor; and

C. grid means responsive to detection signals from the sensing means,

1. said grid means including an operator connected to front and rearbars, said bars reciprocating between an upper position and a lowerposition in response to function of the operator,

2. said grid means further including a plurality of longitudinallyextending, spaced, parallel wires, said wires respectively connectingbetween the front and rear bars,

a. said wires lying within the grid wire receiving slots when the frontand rear bars are in the upper position and said wires positioning belowthe suction boxes when the front and rear bars reciprocate to the lowerposition to thereby push the sheets away from the suction boxes and outof the range of attraction of the fan suction forces.

2. The invention of claim 1 wherein the said slots are of a depthgreater than the height of the wires and wherein the wires positioncompletely within the wire-receiving areas when the bars reciprocate tothe upper position.

3. The invention of claim 2 wherein the said operator includes anair-activated cylinder and a crosshead responsive to the cylinder andrespectively connected to the front and rear bars. v

1. In a sheet-transporting assembly for individually carrying sheets ofmaterial, the combination of A. a continuous suction conveyor carryingthe said sheets by fan suction forces,
 1. said suction conveyorincluding a plurality of parallel, transverse suction boxes arranged inan endless loop, each said suction box being provided with a pluralityof suction openings,
 2. each suction box being provided at the bottomthereof with a plurality of spaced, grid wire receiving slots, a. saidslots extending in the direction of sheet travel and beinglongitudinally aligned to define continuous grid wire receiving areas;B. sensing means detecting the leading edge of each sheet at a preciselocation along the suction conveyor to activate the grid means toseparate the sheet from the suction conveyor; and C. grid meansresponsive to detection signals from the sensing means,
 1. said gridmeans including an operator connected to front and rear bars, said barsreciprocating between an upper position and a lower position in responseto function of the operator,
 2. said grid means further including aplurality of longitudinally extending, spaced, parallel wires, saidwires respectively connecting between the front and rear bars, a. saidwires lying within the grid wire receiving slots when the front and rearbars are in the upper position and said wires positioning below thesuction boxes when the front and rear bars reciprocate to the lowerposition to thereby push the sheets away from the suction boxes and outof the range of attraction of the fan suction forces.
 2. each suctionbox being provided at the bottom thereof with a plurality of spaced,grid wire receiving slots, a. said slots extending in the direction ofsheet travel and being longitudinally aligned to define continuous gridwire receiving areas; B. sensing means detecting the leading edge ofeach sheet at a precise location along the suction conveyor to activatethe grid means to separate the sheet from the suction conveyor; and C.grid means responsive to detection signals from the sensing means, 2.said grid means further including a plurality of longitudinallyextending, spaced, parallel wires, said wires respectively connectingbetween the front and rear bars, a. said wires lying within the gridwire receiving slots when the front and rear bars are in the upperposition and said wires positioning below the suction boxes when thefront and rear bars reciprocate to the lower position to thereby pushthe sheets away from the suction boxes and out of the range ofattraction of the fan suction forces.
 2. The invention of claim 1wherein the said slots are of a depth greater than the height of thewires and wherein the wires position completely within thewire-receiving areas when the bars reciprocate to the upper position. 3.The invention of claim 2 wherein the said operator includes anair-activated cylinder and a crosshead responsive to the cylinder andrespectively connected to the front and rear bars.